The present invention relates generally to filling machines and more specifically to a time flow filling machine for filling containers with a predetermined amount of fluid product.
In the past, filling machines for filling containers with a predetermined amount of fluid product generally utilized positive displacement units of the type described in U.S. Pat. Nos. 3,911,976; 4,004,620; 4,083,389 and 4,294,294. A separate filling unit was associated with each nozzle so that, for example, eight such positive displacement units were used in an eight nozzle machine. An appropriate indexing system would control the movement of the container relative to the nozzles.
Another type of filling machine is known as the constant time-pressure principle. In these machines, the dispensed amount of fluid product is determined by the length of time the valve remains open. Since feed of the fluid product is under constant pressure, the amount dispensed is directly proportional to time. One constant pressure device includes a supply tank being kept under constant pressure by compressed gas, for example. It is costly to maintain the pressure sufficiently constant and eliminate completely fluctuations in pressure which would adversely affect the accuracy of the amount of fluid dispensed.
Other time flow devices are gravity time flow devices using the pressure head of the fluid product in the supply reservoir to the nozzles. For a constant pressure, the liquid level within the supply reservoir must be maintained constant. With fluctuation of the amount of fluid in the reservoir during the dispensing cycle, the flow rate is uneven.
Similarly in the time flow devices, adjustment of the nozzle for various height containers to be transported thereunder changes the distance between a fixed-height supply tank and the nozzle. This changes the head pressure since there is a change in distance between the top of the liquid level in the supply tank and the discharge point of the nozzle. With fixed-height gravity flow tanks, the only way to increase the nozzle flow rate is by means of a pressurized tank or by raising the entire supply tank. This is not only inconvenient but inaccurate.
Time flow systems generally included individual timers for each nozzle to allow adjustment for variations of the characteristics of the nozzle. Set up is very time consuming, especially when each nozzle fills a single container. The adjustment of the timer for one nozzle affects the flow rate of the other nozzles. Therefore, each nozzle must be adjusted and readjusted as other nozzles are adjusted. To avoid these variations, it has been suggested that each of the nozzles be used to fill a portion of a container in a sequence. A typical example is illustrated in U.S. Pat. No. 3,651,836. A first timer is used for one set of nozzles while a second timer is used for a second set of nozzles. In the example given, each of four nozzles fill 1/4 of the total volume into each container.
In certain situations where an exact amount of dispensing is required, a flow meter may be used connected to a pressurized reservoir as illustrated in U.S. Pat. No. 4,401,141. Even further types of filling machines include filling to a desired level using a level sensing device with a fill rate and dribble or top-off rate. These level sensing devices generally fill one container at a time completely or a group of containers using individual control systems. Thus they are very expensive.
Thus it is an object of the present invention to provide an inexpensive time flow, gravity filling machine.
Another object of the present invention is to provide a time flow, gravity filling machine having a constant flow rate despite adjustment for container height.
A still even further object of the present invention is to provide a time flow, gravity filling machine wherein the flow rate for all the bulk fill nozzles can be adjusted simultaneously.
An even further object of the present invention is to provide an inexpensive time flow filling machine with increased accuracy.
Still a further object of the present invention is to increase the throughput of a filling machine while increasing or maintaining accuracy of fill.
Another object of the present invention is to decrease the amount of time required to adjust the machine to dispense a given fill size.
These and other objects are attained by providing a manifold having a supply inlet and supply outlet and one or more nozzles connected to the manifold by individual time controlled valves. A circulation system is provided connecting a supply and the manifold for continuously circulating fluid through the manifold from the supply inlet to the supply or overflow outlet such that the supply outlet determines the fluid level in the manifold and the head pressure at one or more nozzles. The manifold is structured to have a manifold section with a supply inlet on the manifold section and a stand pipe connected to the manifold section. The stand pipe includes the supply outlet and is vented to atmosphere. By varying the height of the stand pipe or the location of the outlet, the level within the manifold and the head pressure at the nozzles is adjusted. This can be varied by replacing the stand pipe with various length stand pipes or by providing an adjustable stand pipe having telescopic sections. A diffuser is provided at the supply inlet which is adjacent the Point at which the stand pipe is connected to the manifold section.
The machine includes a base having a conveyor mounted thereto for positioning containers under the nozzles. A carriage, mounted on the base to move vertically, has mounted thereon the manifold, the nozzles and the time controlled valves. Thus when the carriage is moved vertically for various sized containers, the head pressure at the nozzles does not change since the relationship between the manifold, nozzles and the controlled valves does not change. Substantially straight hoses connect the manifold, the valves and the nozzles so as to maintain the fixed relationship between the fluids in these elements. The nozzles are mounted to the carriage so as to be adjustable in a horizontal plane.
The circulation system includes a pump mounted to the base. A tank, also mounted to the base, may contain fluid to be dispensed. A source of compressed gases and the manifold may be connected to the tank with the supply outlet and vent of the stand pipe closed such that the filling machine may be operated as a pressure, time flow versus a gravity, time flow system. The pump and a level sensor could be used to replenish the tank. The base includes a horizontal frame with a first vertical frame to which the track is mounted and a second vertical frame member to which the carriage mounted. The nozzles are spaced along the longitudinal axis of the manifold which is parallel to track. Each of the nozzles and its respective time controlled valve lie in a plane orthogonal to the longitudinal axis of the manifold.
The controller for the prior art filling machines may include a single timer providing time control to each of the nozzles wherein each of the nozzles fills completely a single container. An indexing system then indexes the same number of containers as there are nozzles. This is in contrast to the present sequential filler where each container would receive a portion of the total fill volume from each of the respective nozzles. In the sequential filling, a single timer would be used for all the bulk fill nozzles except the last nozzle which would be a top-off or fine fill nozzle. This fine fill nozzle has its own separate timer.
For increased throughput, more than one container is indexed in each cycle. For each of the containers to be indexed in a single cycle, a group of bulk fill nozzles and a fine fill nozzle are provided. While each group of the bulk fill nozzles may use a common group timer or its own group timer, each fine fill nozzle requires its own timer.
The amount of fluid dispensed by the fine fill nozzle can be a smaller amount by controlling the time or a different rate by restriction within the nozzle or a combination of both. If desired, the fine fill nozzle can be a level sensing nozzle instead of time flow nozzle. As even a further alternative, it may be desirable to have a sinusoidal dispensing across the longitudinal axis of the manifold. To achieve this, each of the nozzles would have different timers or different flow rates. It is preferred to use a single timer in combination with flow restrictor to achieve different flow rates. The sinusoidal delivery would match the delivery of a single metering device, for example a crank driven piston pump.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.